A quote

"Everything should be made as simple as possible, but not simpler."

And it seems that somebody writes this same source like:

"Everything should be made as simple as possible, but not more so."

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I find the following understanding is good and well-balanced for the above quote:

Perfection is reached when there is nothing left to take away. If there is something there that can be removed without effecting the function, then it is an unnecessary complication and should be removed. If you take away too much then you lose information, utility, or clarity. Thus everything has a minimal form.

.... source: a forum on the Net